Lahaina Water Hardness & Quality Report (2026)
Water Hardness
2.4 grains per gallon
Source
groundwater
pH Level
7.4
neutral = 7.0
Lead
0.004 mg/L
✓ Below action level
TDS
109.4 mg/L
Est. Daily Cost
$0.11
energy & soap waste
Source: USGS Water Quality Portal · Updated 2026
0–60
mg/L
Soft
61–120
mg/L
Moderately Hard
121–180
mg/L
Hard
180+
mg/L
Very Hard
Appliance Damage Report
In Lahaina, your appliances are currently losing 5% efficiency due to mineral buildup.
| Appliance | In Lahaina | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 8.3 yrs | 8.5 yrs | -2% |
| Washing Machine | 12.1 yrs | 12 yrs | — |
| Water Heater | 14 yrs | 15 yrs | -7% |
Regional Water Comparison
How Lahaina compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Lahaina, Hawaii | 40.5 mg/L | 1 ppt | 🟢 Soft | groundwater |
| Wailuku, Hawaii | 23 mg/L | 0.7 ppt | 🟢 Soft | groundwater |
| Kahului, Hawaii | 40 mg/L | 1 ppt | 🟢 Soft | groundwater |
| Kihei, Hawaii | 22 mg/L | 0.7 ppt | 🟢 Soft | groundwater |
| Hawai'i Kai, Hawaii | 56 mg/L | 1.2 ppt | 🟢 Soft | groundwater |
National Benchmark
How Lahaina compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Lahaina | 40.5 mg/L | 🟢 None |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Lahaina's Water Unique?
Local geology and source profile
Lahaina, Hawaii, in Maui County — a Maui County census-designated place on the west coast of Maui, adjacent to Kaanapali in historic West Maui — receives its water from the Maui Department of Water Supply, drawing from West Maui Mountain groundwater wells through the west Maui distribution. *Note: The August 2023 Lahaina wildfire caused widespread infrastructure damage; actual current water data may differ.*
The very soft 40.5 mg/L hardness and low TDS of 109.4 mg/L reflect the West Maui volcanic aquifer supply's very soft character — the Quaternary West Maui Basalt is a highly insoluble olivine basalt formation, and groundwater moves rapidly through lava tubes and dike compartments with minimal time for mineral dissolution (compare Kaanapali HI: 39/106 in Maui County comparable; Wailuku HI: 42/112 in Maui County comparable; Lahaina consistent very soft from the same Maui County West Maui volcanic basalt groundwater supply). The West Maui aquifer — Quaternary West Maui Basalt (insoluble — primary dilutant), Quaternary tuff and ash deposits (insoluble — secondary dilutant), and Holocene coastal alluvium (slightly calcareous — minor TDS).
At 40.5 mg/L with TDS 109, Lahaina's water (pre-disaster) is very soft — virtually no scale buildup. The PFAS level of 1.0 ppt is very low — an excellent result reflecting Hawaii's pristine volcanic aquifer environment. Review the Maui Department of Water Supply's latest annual water quality report for current data.
Geology & Source: Lahaina in Maui County draws from the Maui Department of Water Supply on West Maui groundwater (Maui County, west Hawaii island) — the West Maui Mountains at Lahaina are developed in Quaternary West Maui Basalt (insoluble) and Quaternary tuff deposits (insoluble) — Hawaii Maui County West Maui volcanic basalt groundwater produces very soft water at 40.5 mg/L with TDS 109.4 mg/L.